我试图在一条线的一侧左右对齐并且右侧对齐线的另一侧，但是我很难让右侧向右对齐。有人能抓到我的错误吗？
//The following program will declare
#include <iostream>
#include <iomanip>
using namespace std;
const int HOUSING = 3500; //housing cost
const int MEALS = 2000; //meal cost
const int N_CRED_PER = 285; //out of state credit cost
const int CRED_PER = 130; //amount of money per credit(cost)
const int TAB = 30; //precision
const int ADD_FEES = 6200; //out of state fees for non-resident
int main()
{
cout << "Grant Mercer section 1002 Assignment 6\n\n";
int size, studentID, credits, i, valid,total;
//size of loop, studentID to hold ID of student, credits to hold num
//of credits the student will take, i to start loop
char first, last, res, housing, meal; //first and last to hold initials of
//student, res to hold code
//if student is resident, meal to hold
//code if student has meals
cin >> size; //grab length of loop in file
cout << left; //manipulate stream
cout << fixed << showpoint << setprecision(2);
valid = size; //initially all entries are valid, but de
//cremented each time something goes wrong
while (i < size)
{
cin >> studentID >> first >> last >> credits >> res; //read in mandatory data to vars
cout << setw(TAB) << left << "Student #: " << right << studentID << endl; //display id
cout << setw(TAB) << left << "Initials: " << right << first << last << endl;//display initials
if(credits > 0 && credits < 21) //if credits are fine
{
switch(res) //find char in res
{
case 'R': //if RESIDENT
case 'r':
cout << setw(TAB) << left << "Residency status: " << right << "Resident" << endl;
cout << setw(TAB) << left << "Credits: " << right << credits << endl;
cout << setw(TAB-10) << left << "Tuition: " << setw(10) << "$" << right << (double)CRED_PER * credits << endl;
cout << setw(TAB-10) << left << "Total due: " << setw(10) << "$" << right << (double)CRED_PER * credits << endl;
total += CRED_PER * credits; //add to total cost
break;
case 'N': //if NON-RESIDENT
case 'n':
cout << setw(TAB) << left << "Residency status: " << right << "Non-resident" << endl;
cin >> housing >> meal; //since the student is non-resident, they
//have a mean and house code
cout << setw(TAB) << left << "Credits: " << right << credits << endl;
cout << setw(TAB - 10) << left << "Tuition: " << setw(10) << "$" << right << (double)credits * N_CRED_PER + ADD_FEES << endl;
if(housing == 'H' || housing == 'h')
{
cout << setw(TAB - 10) << left << "Housing: " << setw(10) << "$" << right << (double)HOUSING << endl;
if(meal == 'M' || meal == 'm') //if MEALS
{
cout << setw(TAB-10) << left << "Meal Plan: " << setw(10) << "$" << right << (double) MEALS << endl;
cout << setw(TAB-10) << left << "Total due: " << setw(10) << "$" << right << (double) MEALS + HOUSING + (credits * N_CRED_PER) + ADD_FEES << endl;
total += MEALS + HOUSING + (credits * N_CRED_PER) + ADD_FEES;
//add to total
}
else //if NO MEALS
{
cout << setw(TAB-10) << left << "Total due: " << setw(10) << "$" << right << (double)\
HOUSING + (credits *N_CRED_PER) + ADD_FEES << endl;
total += HOUSING + (credits * N_CRED_PER) + ADD_FEES;
//add to total
total += HOUSING + (credits * N_CRED_PER) + ADD_FEES;
//add to total
}
}
else //if NO HOUSING NO MEALS
{
cout << setw(TAB-10) << left << "Total due: " << setw(10) << "$" << right << (double)(cr\
edits * CRED_PER) + ADD_FEES
<< endl;
total += (credits * CRED_PER) + ADD_FEES;
}
break;
}
}
else
{
cout << "INVLIAD CREDIT AMOUNT...\n";
valid--;
}
i++;
cout << endl << endl;
}
cout << "\nFINAL TOTALS\n"; //display final totals from students
cout << right << setw(TAB) << left << "Valid request count: " << right << valid << endl;
cout << setw(TAB) << left << "Invalid requrest count: " << right << size - valid << endl;
cout << setw(TAB - 10) << left << "Total feed due: " << setw(10) << "$" << right << (double)total;
cout << endl;
return 0;
}
输出都是左对齐的，我不明白我需要做什么才能使这一切正确。谢谢！
答案 0 :(得分：4)
在使用setw()打印每个右对齐字符串之前，您忘记使用cout。例如，在代码中使用以下行：
cout << setw(TAB) << left << "Residency status: " << right << "Resident" << endl;
在打印向左或向右对齐的每个字符串之前，必须设置一个新的宽度：
cout << setw(20) << left << "Residency status: " << setw(20) << right << "Resident" << endl;
如果没有setw()，则假设宽度为零，这基本上忽略了正确的对齐。